Tearing of the medial palmar intercarpal ligament in the equine midcarpal joint.

This study documents the occurrence of medial palmar intercarpal ligament tears in 42 horses who were referred for arthroscopic surgery. The study found that tearing was most commonly observed in conjunction with other carpal issues like osteochondral chip fragments, and the degree of ligament damage ranged from 10% to 100% of the ligament’s width.

Study Overview and Methodology

• The research focuses on the tears in the medial palmar intercarpal ligament in horses. This ligament is located within the horse’s midcarpal joint, a commonly affected joint in equine leg injuries.
• The study included 42 horses, out of which 37 were racehorses, and 5 were non-race horses. The racehorses included various breeds: 20 Quarter Horses, 14 Thoroughbreds, and 3 Standardbreds.
• All these horses were referred for arthroscopic surgery – either for removal of osteochondral chip fragments that had been diagnosed on radiographs or diagnostic arthroscopy due to persistent carpal issues.

Findings

• Ligament tearing was found in 45 intercarpal joints in these 42 horses, being unilateral in 39 horses and bilateral in 3 horses.
• The presenting symptoms were lameness (a deviation from regular gait or stride, commonly due to pain) and/or continuous synovial effusion (excessive fluid in the joint). In one case, the horse had haemarthrosis (bleeding into joint spaces).
• Osteochondral chip fragments were present in the joint of 23 horses suffering from ligament tear. In 6 other horses, these fragments were found within other joints, but the synovial effusion was most severe in the joint with the ligament tear.

General Observations

• In 22 cases, where both carpal chip fragmentation and ligament tear were found together, the clinical severity was found to be more than what is usually associated with that level of osteochondral fragmentation.
• A ligament was acknowledged as torn if a defect was seen in it, usually in the form of frayed fibres visible in the irrigating solution during arthroscopy.
• The damage to the ligament ranged from 10% to 100% of the width of the ligament.

This study highlights the complex nature of carpal ligament injuries in horses and the associated factors. Such findings could aid in the diagnosis and treatment of equine limb injuries.